Pulmonary carcinogenesis with inhaled Plutonium in rats and dogs

Pulmonary carcinogenesis, after inhalation of 239PuO2, in rats and in dogs was compared. Both for rats and dogs, the exposure regimes gave the highest tumor incidence in the dose range of 1400 to 11,000 rads to the lung, with lung tumor incidences in rats and dogs that lived longer than the shortest latency periods of 54 and 84%, respectively. Survival time was inversely proportional to the average rads per day dose in both dogs and rats. The latency period for lung tumors was longer for dogs than for rats except when calculated as percent of life span, in which case the rats had a longer latency period. The tumors developed in peripheral areas of the lungs of both rats and dogs and consisted most frequently of adenocarcinomas in rats and bronchiolo-alveolar carcinomas in dogs. Other tumors included epidermoid carcinomas in both dogs and rats, adenosquamous carcinomas in dogs, hemangiosarcomas in rats, and one mesothelioma in a rat. Radiation pneumonitis and pulmonary fibrosis were widespread in both rats and dogs